If he's the lead designer of WoW, then he'll probably talk about WoW. Maybe he'll announce something similar to Guild Wars - as in a new 'chapter' to the game. Or a brand new game entirely.
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Welcome to Zelaron, btw. Nice spelling and grammar.
I went last year and quite enjoyed myself (and learned a few things). Austin is a hoot. The best part is LivePitch. It's sort of like American Idol for game developers. If you've got a game to pitch, http://www.livepitch.com.